1. Field of the Invention
The present invention relates generally to heat exchangers for motor vehicles and, more specifically, to a manifold and method of making same for a heat exchanger in a motor vehicle.
2. Description of the Related Art
It is known to provide a heat exchanger such as a condenser for an air conditioning system of a motor vehicle. The heat exchanger typically includes a plurality of U-shaped tubes having a fluid passing therethrough and a plurality of fins extending between the tubes. The number of U-shaped tubes depends on thermal capacity requirements of the heat exchanger. In order to connect these tubes together so that the fluid can flow through the tubes, manifolds are used having a series of openings corresponding to and mating with the ends of the tubes. The manifolds have an inlet port and an outlet port which circulate the fluid through the heat exchanger and then return the fluid to a remote location for subsequent recycling.
It is also known to fabricate manifolds as an extrusion using an extruding process. An example of such a method to make a manifold is disclosed in U.S. Pat. No. 5,190,101. In this patent, a manifold for a heat exchanger is fabricated by extruding a generally planar base member with a U-shaped channel disposed below a plane thereof and a pair of vertically depending walls projecting generally perpendicularly to the plane of the base member. The method includes forming a plurality of fluid conducting passageways in the base member and rolling the vertical depending walls toward a longitudinal center of the base member until the free ends of the walls are disposed in the channel of the base member to form fluid conduits. However, these extruded manifolds are relatively expensive to produce.
It is further known to fabricate manifolds as a stamping using a stamping process. An example of such a method to make a manifold is disclosed in U.S. Pat. No. 5,163,509. In this patent, a manifold assembly for a heat exchanger includes a first manifold and a second manifold. The first manifold has a first hollow conduit and a first plurality of apertures through the first conduit. The second manifold has a second hollow conduit and a second plurality of apertures through the second conduit. The manifold assembly includes at least one joining member between the first and second manifolds for joining the first manifold to the second manifold with the first conduit being side-by-side and adjacent the second conduit. The joining member includes a region of weakness for facilitating separation of the first and second manifolds. The manifold assembly is fabricated by stamping and bending a single elongate sheet metal strip.
Although the above manifolds have worked, they suffer from the disadvantage that the extruded manifolds are relatively costly to manufacture. Another disadvantage of the above manifolds is that the stamped manifolds have a portion extending above the plane of the fluid conduits. Yet another disadvantage of the above manifolds is that the stamped manifolds have a pair of seams that are brazed which may result in leakage of fluid if not brazed properly. Still another disadvantage of the above manifolds is that extruded manifolds have a U-shaped channel disposed below a plane of the base member, which is undesired. Therefore, there is a need in the art to provide a manifold for a heat exchanger of a motor vehicle that overcomes these disadvantages.